Proton NMR Spectroscopy has so far been used to characterize aspects of the solution-state structure and heme-pocket associated dynamics of two proteins: the heme enzyme Cytochrome c Peroxidase from yeast and the myoglobin-like proteins that are monomer hemoglobins and which are derived from the marine annelid Glycera dibranchiata. Both classes of proteins have been cloned and are currently in expressions systems that are in our possession. So far several mutants of the monomer hemoglobin Component IV have been made and purified in our laboratory. With respect to the goals of this work and our use of NMRFAM, we would like to pursue the following studies. 1. Glycera dibranchiata Monomer Hemoglobin Component IV (GMH4): We would like to doubly label this expressed protein 13C/15N) and determine its solution 3-dimensional structure. This protein is ~16 kD and the structure is quite important because there is no reliable structure of this unusual heme-globin. 2. Yeast Cytochrome c Peroxidase: We would like to begin making amino acid assignments in H2O medium. We cannot do this at WSU because we have no capability for pulse tailoring or gradient enhanced spectroscopy. This protein is big by NMR standards (35 kDa) so there will be few benefits of employing higher fields with it, and 500 MHz seems about the optimal spectrometer system.